470 



Transactions. — Chemistry and Physics. 



Differences. 



pear to show the regular formation of a maximum at the 

 number 29 : — 



Table VIII. 

 Boiling- 

 point. 

 51-52° 

 78-80 

 100-101 

 127-128 

 145-146 

 174-175 

 194-195 

 220 



26-5 



27 



29 



26 



21-5 



18-5 



20 



Acetyl chloride 



Propionyl „ 



Butyryl „ 



Valeryl „ 



Hexoyl „ 

 Heptoyl 



Octoyl „ 



Nonoyl „ 



This maximum occurs in the same series as the maximum 

 shown by the esters and the acids themselves, but one place 

 higher. The acid chlorides also differ from the esters and the 

 acids themselves, by the fact that the average for the set of 

 larger differences (27) is considerably greater than the corre- 

 sponding number (22) for the acids and their ethereal salts. 

 On the other hand, a resemblance is shown to the esters' 

 slight differences between the numbers of the same set, while 

 this is not the case among the acids. This, then, is the true 

 test for the magnitude of the molecular complexity of the 

 gaseous molecule at the boiling-point. 



Acids of the oxalic series tend to decompose when heated, 

 consequently their boiling-points cannot be determined under 

 the ordinary conditions. Krafft," however, has determined 

 the boiling-points of some of the higher members under re- 

 duced pressure. The results show the usual waviness, but 

 the differences are smaller than for the corresponding fatty 

 acids under the same conditions. Hence it is reasonable to 

 conclude that the association of the dibasic acids in the state 

 of vapour is less than that of the fatty acids from which they 

 are derived.! 



Table IX. 





*Ber., 22, 816. 



f In phenol solution, although sebacic acid associates more rapidly than 

 the corresponding fatty acid, the initial association of the latter is greater. 



